BITING MIDGES WIRTH AND BLANTON 



253 



new Honduras and Nicaragua records are based on material collected 

 in liglit traps operated in the yellow fever surveys by the Gorgas 

 Memorial Laboratory under the direction of Pedro Galindo. 



Our measurements are made with an ocular micrometer and, with 

 rare exceptions, are of specimens cleared in phenol and mounted on 

 slides in balsam. Measurements are usually made of a series of about 

 10 specimens and are presented in the descriptions according to the 

 following system: "mean (minimum-maximum, n = number of mea- 

 surements)." Measurements not given in that manner are of single 

 specimens. 



Morphology 



FiGUEES 2, 3 



The descriptions and figures of the structure of Culicoides given by 

 Carter, Ingram, and Macfie (1920) are still classical, although valuable 

 studies on the head structure have since been made by Jobling (1928) 

 and Gad (1951), and on general anatomy by Tokunaga (1937) and 

 Lee (1948). The following account is a revision of the generalized 

 description of characters of the Heleidae given by Wirth (1952a). 



Head: The head is subspherical, with the anterior surface more 

 or less flattened and in line with the anterior surface of the proboscis. 

 The dorsal surface of the head consists of the broad posterior occiput 



Figure 2. — Culicoides diabolicus Hottman, dorsal aspect of female. 



